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Pasteurization/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim takes a carton of milk from his kitchen refrigerator. He sniffs the carton's opening and frowns. TIM: Moby? Has this gone bad? Tim hands the carton to Moby. MOBY: Beep. Moby sticks out a pointer finger. The end of the finger opens, and a tube comes out. The tube snakes into the milk carton. A few moments pass as Moby analyzes the milk, and his eyes turn green. MOBY: Beep. Moby's eyes return to normal. TIM: Thanks. Tim drinks milk from the carton. TIM: Aaah. Tim reads from a typed letter. TIM: Dear Tim and Moby, does pasteurized milk come from special cows? Sincerely yours, Ella. Nope. Pasteurized milk comes from regular cows. An animation shows a smiling cow standing in a farmer's field. TIM: Pasteurization means that the milk has been heated up to a temperature high enough to destroy any germs that could make you sick. The heat also destroys enzymes that make milk spoil, so pasteurized milk stays drinkable for a longer time. An animation shows a lab technician supervising the pasteurization of an open vat of milk. Germs and enzymes in the milk disappear as the process proceeds. TIM: The process is named for the French scientist Louis Pasteur. An image shows Louis Pasteur. TIM: During the 1860s, he figured out that wine and beer could be kept from spoiling if they were heated to about fifty-seven degrees Celsius for a few minutes. An image shows Pasteur experimenting with his process. TIM: Eventually, people figured out that the same process could be applied to other foods and drinks, especially dairy, to make them safer to eat and drink. Images show a carton of milk, a piece of cheese, an egg, a bottle of soda, a carton of orange juice, and a can of beets. MOBY: Beep. TIM: Well, if you milk a healthy cow, the milk will usually be safe to drink. An animation shows a boy on his back beneath a cow. He squeezes the cow's udder and squirts white milk into his mouth. TIM: But dairy farms at the at the start of the twentieth century, they were often dirty filled with sick cows and sick people. An animation shows the boy on his back beneath the cow. The boy, the cow, and the surroundings are filthy and diseased-looking. Flies buzz around. The boy squeezes the cow's udder and squirts yellow-brown milk into his mouth. TIM: Bacteria often ended up in the milk, making dairy products unsafe to consume. An animation shows a cow coughing germs into a bucket of milk. TIM: Pasteurization made milk safer, and the United States Food and Drug Administration, or FDA, began to pass laws to require it. An image shows the symbol of the Food and Drug Administration. TIM: By the 1950s, any dairy products that were going to be sold across state lines had to be pasteurized. An animation shows boxes moving along an assembly line. Text on each box reads: Grade A Milk, Pasteurized. MOBY: Beep. TIM: Like any technology, pasteurization has changed over the years. Louis Pasteur's method involved heating liquids in large vats for long periods, up to thirty minutes. An animation shows an early method of pasteurization. Milk is heated in a large, sealed vat, with a blade inside the vat stirring the milk. A stopwatch times thirty minutes. TIM: That's called low-temperature, long-time pasteurization, or LTLT. Nowadays, liquids are usually heated to very high temperature for short times, in a process called high-temperature, short-time pasteurization, or HTST. An animation shows a modern-day pasteurization process. It involves a more complicated apparatus and less processing time. TIM: HTST is better than the old way at preserving the nutrients and quality of food. MOBY: Beep. TIM: Well, pasteurization does change the food a little bit, although not everyone agrees on how important the changes are. Some of it depends on how hot the liquid has been heated. The milk that you find at a grocery store might have gone through one of three types of pasteurization. Pasteurized milk has been heated up to seventy-two degrees Celsius for fifteen seconds. Pasteurized milk should last about two weeks in the fridge. Ultra-pasteurized milk has been heated up to one hundred and thirty-eight degrees Celsius for only two seconds. These liquids can be kept in your refrigerator for up to ninety days. Finally, ultra-high temperature pasteurization heats milk up to one hundred and fifty degrees Celsius for one or two seconds. Liquids that have been treated in this way can stay unrefrigerated for several months if they're packaged right. An image shows all three types of milk that Tim describes. Pasteurized and ultra-pasteurized cartons of milk are in a refrigerator. An ultra-high temperature pasteurized carton of milk is stored on an unrefrigerated shelf. TIM: So there you have it. Pasteurization, keeping our milk safe and healthy. Tim takes another long drink from his carton of milk. He looks around and sees nobody. He opens the refrigerator to put the milk back inside. Moby suddenly appears. MOBY: Beep. Moby frowns. He is unhappy with Tim. TIM: What do you care? You don't even drink milk. MOBY: Beep. Tim frowns. TIM: Fine. Instead of putting the carton of milk in the fridge, Tim throws it in the garbage can. Category:BrainPOP Transcripts